This blood obstruction, called a “fibrocartilaginous embolic myelopathy”, depletes the oxygen supply to the spinal cord, and the cells in the spine begin to malfunction and die off. This leads to limb paralysis and neurological damage. The effects of the obstruction will vary depending on where it is located. Damage to the portion of the spinal cord in the neck will lead to front limb problems, whereas damage to the area between the shoulder blades will affect the back limbs. One side of the body is often affected more than the other. Cases range greatly in severity. Fibrocartilaginous embolic myelopathies tend to happen during times of physical activity, and occur more often in middle-aged cats. The damage to the nervous system in the first 24 hours after the blockage may be permanent. 

A cat's spine is composed of vertebrae (bones) which are held together by intervertebral discs that allow slight movement and absorb shocks to the spine. These discs are made up of fibrocartilaginous material, which is a combination of cartilage and collagen. The collagen makes the cartilage more flexible. In some instances, this fibrocartilaginous material can break off of the disc and enter into the bloodstream. Once in the blood, it is capable of causing full obstructions in the blood vessels, creating a stroke-like reaction to the spinal cord. 

This condition often has a very rapid onset with symptoms being present moments after the obstruction has taken place and gradually worsening over the next 12 to 24 hours. While initially some pain may be felt, the issue is usually not associated with pain as paralysis takes over. All signs to watch for include:

The reason that fibrocartilaginous materials break off from the disc and enter into the bloodstream is generally unknown. It is thought that the center of the disc is the portion that separates and enters into the vertebral blood vessel. Vigorous activity is thought to trigger this occurrence.

Upon arriving at a veterinary clinic or animal hospital, be sure to provide the veterinarian with your cat's full medical history. The vet will perform a complete physical examination of the cat, palpating the spinal area to see if any pain response follows. Cases of fibrocartilaginous embolic myelopathy generally are not painful, so this can help differentiate a blockage from a traumatic injury. Other issues that will need to be ruled out include cancers of the spine, infections, and inflammation. 

A neurological examination will also be performed. The overall movement and mobility of the cat will be assessed. Tests will be administered to determine whether or not the cat has any feeling left in the affected limbs. These evaluations will also help locate the area where the blockage has taken place. Spinal x-rays including myelography (x-rays with the use of dye for clarification) can be helpful in showing a thinning of subarachnoid space without any spinal compression. An MRI may reveal swelling in the spinal cord. Cerebrospinal fluid may be collected and microscopically examined for an increase in neutrophils (white blood cells). A definite diagnosis can only be made post-mortem with a histopathological examination of spinal blood vessels.  

There is no way to remove a piece of fibrocartilaginous material from the blood vessel as of yet. Treatment is mainly symptomatic to help restore movement to the cat.

If the cat has been diagnosed within six to eight hours of the blockage occurring, a vigorous intravenous treatment including corticosteroids may prevent more neurological damage from happening. The cat may need to be propped in an upright position during this time.

The best treatment for fibrocartilaginous embolic myelopathy is physical therapy started as soon as possible after the blockage has developed. These treatments can help maintain muscle tone and increase the mobility in the affected limbs. Possible treatments that may be recommended include massage therapy, hydrotherapy, acupuncture, neuromuscular electrical stimulation and stretching exercises.

During the recovery process, an extensive at-home care regimen may be needed for a long period of time. It is not uncommon for cats who have suffered from a fibrocartilaginous embolic myelopathy to become incontinent. Moving the litter box close to the cat's bed may help with this problem, but some cases will require manual expression of the bladder. You will need to regularly rotate your cat to keep it comfortable and to prevent bed sores from forming. Soft bedding can also help with this issue. 

A follow-up appointment with the veterinarian will be needed approximately two weeks after treatment has been started. The vet will note all improvements in movement and neurological function. If no improvement has been seen by the third week, the prognosis may be poor. Most cats regain the ability to walk in the months that follow. A second fibrocartilaginous embolic myelopathy is not likely to occur. There are no known ways to prevent this health problem. Giving your cat regular supplements such as Vitamin B, antioxidants, and certain enzymes can support the health of the spinal column and cord.